Igniter



July l2, 1966 R. J. zoscHAK ETAL 3,260,301

IGNITER Filed Feb. 20, 1964 VENTORS OJCHA K 9065er SOMMEFZAQ Bu/n mmfATTORNEY United States Patent O 3,260,301 IGNITER Robert J. Zoschak,Rutherford, and Robert E. Sommerlad, Cranford, NJ., assiguors to FosterWheeler Corporation, New York, N.Y., a corporation of New York FiledFeb. 20, 1964, Ser. No. 346,315 Claims. (Cl. 15S- 115) This inventionrelates to igniters and more particularly to igniters using a gaseousfuel.

In the construction of gas-burning igniters, it is very important toachieve stability of combustion. According to this invention in order toobtain the desired stability, a pilot chamber is annularly disposedwithin an outer partition. In the space between the outer shield and thepilot chamber, a passageway is formed for supplying air to the llameport and for locating a series of individual conduits which deliveredcombustible gas to the flame port. Apertures in the pilot chamber permita limited quantity of air from the passageway to enter the pilotchamber. An orifice plate at the outboard end of the pilot chamberpermits only a limited quantity of combustible gas to enter the pilotchamber.

Also important in the construction of igniters is to provide for longlife for preventing the heat of the burner -being ignited fromdeteriorating such heat destructible parts of the igniter as the pilotignition system. In accordance with this invention, this is achieved bylocating such parts as remotely as possible from the burner heat. Suchremotely located parts also provide for easier maintenance of theigniter.

An object of this invention is to provide an improved igniter.

` Another object of this invention is to provide an igniter withvstability of combustion.

Still another object of this invention is to provide an igniter whichavoids deterioration from burner heat.

kend of the apparatus embodying the invention joined on the lines a-a ofFIGURE 1.

FIGURE 2 is a transverse section taken on line 2-2 of FIGURE 1.

FIGURE 3 is an inboard end view of the apparatus embodying theinvention.

Referring now to the drawings and particularly to FIG- URE 1, theigniter has an outboard portion, generally designated by the numeral 11,which is located outside a furnace or other burner enclosure (notshown). The igniters inboard portion, generally designated by thenumeral 12 and shown in FIGURE 1A, is located inside a furnace. Theinboard portion 12 has a flame port 13 located at its extreme inboardend. The igniter passes through a wall (not shown) of the furnace and isso placed that the llame port 13 is adjacent the burner of the furnace.In this way the apparatus serves to ignite combustible fuel when it isemitted from the burner.

An outer partition 14 forms the outside surface of both the outboardportion 11 and the inboard portion 12 of the igniter. A shell 18encloses the extreme outboard end of the outboard portion 11. A flange15 is connected to the shell 18. A similar flange 16 is connected to theouter partition 14. A plate 19 ts between the flange 15 and the flange16. The flanges 15, 16 are pressed against the plate 19 by means ofbolts 20. Seals 21 are used rice between the plate 19 and the flanges15, 16 to prevent leakage. A gas inlet 23 opens into the shell 18 whichdefines a gas-collection compartment 25.

Within the outer partition 14 is a inner partition 27 which, as shown inFIGURE 1A, is withdrawn slightly within the outer partition 14 at thellame port 13. The space encompassed by the inner partition 27 defines apilot chamber 28 which is open at the flame port 13. The opposite end ofthe inner partition 27 has an orifice plate 29 secured to it. Orifices31 provide multiple small passageways through the orifice plate 29. Thetotal crosssectional area of the orifices 31 is controlled by the amountof combustible fuel desired within the pilot chamber 28 formed by theinner partition 27. A cyclindrical lip 32 protrudes from the orificeplate 29 thereby defining a threaded cavity 33. A plug 35 is screwedpart-way into the threaded cavity 33 to leave a space 37 between theplug 35 and the orifice plate 29. A threaded opening 38 is locatedthrough the center point of the plug 35.

Located approximately at the center point of the end plate 19 is athreaded opening 40. Threaded into the opening 40 is a bushing 41 whichsecures a pilot gas-supply tube 43 to the plate 19. The opposite end ofthe pilot gas-supply tube 43 is screwed by means of a fitting 45 to thethreaded opening 38 in the plug 35. The pilot gas-supply tube 43 therebydefines a passageway cornmunicating between the gas-collectioncompartment 25 and the space 37 between the plug 35 and the orificeplate 29.

An annular space 39 is located between the inner partition 27 and theouter partition 14.v yA series of tubes or conduits 48 pass through thespace 39 and extend beyond the outer partition 14 as shown in FIGURE 1A.At the flame port 13 the4 conduits 48 are bent, and the llame orifices52 are attached. The opposite ends of the conduits 48 pass throughthreaded openings 42 in the end plate 19. Bushings 44 are screwed intothe openings 42 to seal the connection between conduits 48 and the endplate 19. U-members 46 are circumferentially placed in a spaced relationto assure separation between the conduits 48. As gas is supplied intothe compartment 25 through the gas inlet 23, a major portion of the gasflow passes through the conduits 48 and a minor portion of the flowpasses through the tube 43 to the pilot chamber 28. The bend at theinboard end and the orientation of the conduits 48 causes thecombustible gas being discharged fmom the conduits 48 at lthe flame port13 to swirl inwardly.

An air inlet 47 is provided through the outer partition 14. Largeapertures 49 are provided in the inner partition 27 to permit a minorportion of the air flow to enter the pilot chamber. A major portion ofthe air stream flows through a number of passageways 50 which are formedfrom the portion of the annular space 39 not occupied by the conduits48. An adjustable sleeve 51 may be provided having perforations 53therein to regulate the cross-sectional area available for the flow ofair through the large apertures 49. Use of a sleeve 51 as well as thenumber and sizing of the apertures is, of course, a matter of choice.Small apertures 55 are provided in spaced locations about thecircumference of the inner partition 27 to provide additional air to aflame in the pilot chamber 28 as the flame approaches the llame port 13.

A spark plug 57 is provided which extends into the pilot chamber 28 toprovide a spark therein for ignition of a pilot flame. A sight port 59is located in line with an aperture 61 which is one of the group ofsmall apertures 55 to permit viewing into the pilot chamber 28 through atransparent sheet 62.

In operation, combustible gas is supplied through gas inlet 23 intocompartment 25. A major portion of the gas flow passes into conduits 48which deliver the gas directly to the flame port 13. The bent ends andorientation of the conduits 48 swirl the gas streams inwardly. A minorportion of the gas passes through tube 43. Air is supplied through airinlet 47. A major portion of the air flows through passageways 50between the conduits 48 to llame port 13. A minor portion enters thepilot chamber 28 through the apertures 49, 55. When the spark plug 57 iselectrically charged, a spark lire-s the gas and air mixture in thepilot chamber 28 and the flame in the pilot chamber 28 burnscontinuously through the full length of the inner partition 27. As theame progresses toward the llame port 13, additional air continuescombustion. This additional air which enters through the variousapertures 55 is necessary to completely burn all the ga-s entering thepilot chamber 28 since the amount of air entering through the apertures49 is inadequate for full burning of the gas being supplied through theorices 31. The pilot llame emerges from the pilot chamber 28 ignitingthe gas and air being discharged at the llame port 13. As soon as thespark begins burning in the pilot chamber 28, the spark plug S7 need nolonger be electrically charged. The flame thus burning at the flame port13 serves to ignite a burner located nearby.

It is to be understood that the above-described arrangements are simplyillustrative of the application of the principles of the invention.Numerous other arrangements may be readily devised by those skilled inthe art which will embody the principles of the invention and fallwithin the spirit and scope thereof.

What is claimed is:

1. An igniter for fuel burners comprising:

an outer partition defining a llame port at one end,

an inner partition with apertures therein located within said outerpartition so that an annular space is formed between said innerpartition and said outer partition and a pilot chamber is formed withinsaid inner partition,

conduits occupying a portion of said annular space,

means for introducing combustible gas to said conduits and to said pilotchamber,

means for limiting the portion of combustible gas flowing into saidpilot chamber so that a major portion of said combustible gas flowsthrough said conduits to said flame port and a minor portion of saidcombustible gas flows into said pilot chamber,

an air inlet for introducing air, said air flowing through said annularspace around Isaid conduits, a major portion of said air beingdischarged from said annular space at said llame port and a minorportion entering said pilot chamber through said apertures, and asparker in said pilot chamber to cause a pilot llame to burn in saidpilot chamber, said pilot flame causing the combustible gas llowing fromsaid conduits to burn at said llame port.

2. An igniter according to claim 1 wherein:

said conduits extend beyond said outer and inner partition and arearcuately shaped at the flame port so as to swirl the combustible gas asit is discharged therefrom.

3. An igniter according to claim 1 wherein:

said outer partition extends slightly beyond said inner partition atsaid llame port, and

said conduits extend beyond said outer partition, the

extending portions being arcuately shaped.

4. An igniter for fuel burners comprising:

an outer partition having an inboard end and an outboard end, saidinboard end defining a flame port,

an inner partition with apertures therein located within said outerpartition so that an annular space is formed between said innerpartition and -said outer partition and a pilot chamber is formed withinsaid inner partition, said inner partition having an inboard end and anoutboard end,

a shell forming a compartment at the outboard end of said outerpartition,

an inlet for introducing combustible gas into said shell,

conduits extending from said compartment through said annular space tosaid flame port to provide a passageway for said combustible gas,

an orifice plate between said compartment and said pilot chamber forlimiting the portion of combustible gas llowing into said pilot chamberso that a major portion of said combustible gas flows through saidconduits to said llame port and a minor portion of said combustible gasilow-s into said pilot chamber,

an air inlet for introducing air, said air flowing through said annularspace and around said conduits, a major portion of said air beingdischarged from said annular space at said flame port and a minorportion entering said pilot chamber through said apertures, and

a sparker in said pilot chamber to cause a pilot flame to burn in saidpilot chamber, said pilot flame causing the combustible gas flowing fromsaid conduits to burn at said llame port.

5. An igniter according to claim 4 wherein the outer partition and innerpartition are concentric cylinders.

References Cited by the Examiner UNITED STATES PATENTS 12/1964 Ihleneld158-109 X 2/1965 Zoschak 158--115

1. AN IGNITER FOR FUEL BURNERS COMPRISING: AN OUTER PARTITION DEFINING AFLAME PORT AT ONE END, AN INNER PARTITION WITH APERTURES THEREIN LOCATEDWITHIN SAID OUTER PARTITION SO THAT AN ANNULAR SPACE IS FORMED BETWEENSAID INNER PARTITION AND SAID OUTER PARTITION AND A PILOT CHAMBER ISFORMED WITHIN SAID INNER PARTITION, CONDUITS OCCUPYING A PORTION OFSAIDF ANNULAR SPACER, MEANS FOR INTRODUCING COMBUSTIBLE GAS TO SAIDCONDUITS AND TO SAID PILOT CHAMBER, MEANS FOR LIMITING THE PORTION OFCOMBUSTIBLE GAS FLOWING INTO SAID PILOT CHAMBER SO THAT A MAJOR PORTIONOF SAID COMBUSTIBLE GAS FLOWS THROUGH SAID CONDUITS TO SAID FLAME PORTAND A MINOR PORTION OF SAID COMBUSTIBLE GAS FLOWS INTO SAID PILOTCHAMBER, AN AIR INLET FOR INTRODUCING AIR, SAID AIR FLOWING THROUGH SAIDANNULAR SPACE AROUND SAID CONDUITS, A MAJOR PORTION OF SAID AIR BEINGDISCHARGE FROM SAID ANNULAR SPACE AT SAID FLAME PORT AND A MINOR PORTIONENTERING SAID PILOT CHAMBER THROUGH SAID APERTURES, AND A SPARKER INSAID PILOT CHAMBER TO CAUSE TO PILOT FLAME TO BURN IN SAID PILOTCHAMBER, SAID PILOT FLAME CAUSING THE COMBUSTIBLE GAS FLOWING FROM SAIDCONDUITS TO BURN AT SAID FLAME PORT.